У оквиру семинара Групе за гравитацију, честице и поља, у петак, 30. октобра 2026. у 11 часова у Сали 360 (други спрат) Института за физику у Београду, предавање:
Model of fundamental decoherence and nonunitarity in quantum electrodynamics
одржаће Милош Петрашиновић.
САЖЕТАК:
This talk will present a phenomenological model of fundamental decoherence in quantum electrodynamics, based on the assumption that the off-shell virtual particles can lead to a loss of quantum coherence. This mechanism is introduced by modifying internal electron and photon propagators with exponential factors that depend on the square of the four-momentum. Deviations from standard propagation are governed by the characteristic scales Λₑ and Λγ. The electron–photon interaction retains its vector form, while the photon is described by a massive Proca field.
Decoherence is modeled as an interruption of coherent propagation along an internal line of a Feynman diagram. The probability of this process is related to the modification of the propagator, and the resulting state is described by the density matrix of a thermalized ensemble. The corresponding statistical distribution is specified by the choice of fluctuation energy and by constraints on the mean four-momentum and the mean squared four-momentum. On this basis, statistical contributions from diagrams with a single interrupted internal line are formulated.
Particular attention will be devoted to isolating the contributions arising from the modified propagators and exploring how they can be probed through the electron’s anomalous magnetic moment, the Lamb shift, and scattering probabilities. This establishes a framework for examining the physical implications of the model and possible experimental constraints on its characteristic scales.